The proximity of various communication devices that transmit energy to a reference communication device that receives that energy may be detected at the reference communication device based on the received energy. The reference communication device may receive radio frequency (RF) signals, ultrasound signals, and sound signals that are perceptible to human hearing, such as voice signals, from the other communication devices. The reference communication device typically includes application modules that subject the received energy to signal processing, such as RF demodulation, echo cancellation, and voice recognition that renders the received energy, in whatever form, unavailable, unsuitable, or not easily accessible for use in proximity detection algorithms. The received energy may not readily convert to physical proximity. Moreover, the application modules may be inaccessible or otherwise difficult to modify so as to incorporate the proximity detection algorithms. In such environments, proximity detection may only be implemented as a complex “work-around” of, or an “add-on” to, existing signal processing/application modules and can, therefore, be expensive and less effective than desired.